Electrorheostat-regulator.



H. GERNSBACK.

ELECTRORHEOSTAT REGULATOR.

Patented Feb. 1, 1910.

APPLICATION FILED SEPT.1,190B.

. UNITED sTATEs HUGO GEBNSBACK, OF NEW YORK, N. Y. i

ELECTRORHEOSTAT-REGULATOR.

Specication of Letters Patent.

Patented Feb. 1, 1910.

Application led September 1, 1908. Serial No. 451,186.

vYork, in the county of NewYork and State -of New York, have invented certain .new

, and 'useful Improvements in Electrorheoestat-Regulators, of which the following is a full, clear, and exact specification.

My invention relates to electro-rheostat regulators and the provision4 of means for carefully and accurately regulating'the iiow of current in any electric circuit by gradually cutting in andv out part of a resistance kcoil composed of numerous convolutions of wire, and in which resistance coil a variation is obtained by means of a movable spring-seated ball bearing contact point, which engages the upper exposed surface of the resistance coil with a minimum amount of friction. My invention,r` however, is more particularly directed to thevform and construction of the base .and in the manner of holding4 the resistance coil in place by means of an uninterrupted annular undercut retaining groove with a sufficient opening at the top thereof to enable the coil to be sprung lengthwise intoposition lengthwise. i

Among-the objects of my invention is the provision of a simple, e cient, small-sized and compact rheostat, in which there are no concealed parts and which by reason of its construction and mode of operation will insure a gradual and almost imperceptible regulation of current.r My improved rheostat possessesl` great current capacity, and produces little or lno heating because the parts are open tothe air and are therefore air cooled. f

Another object is to provide a resistance coil com osed of numerous -convolutions of wire and) which coil is hollow.k The resistance coil -has an extremely wide range of resistance in .a very small space, and is of simple, practical and inexpensive construction and by reason of being hollow produces a maximum amount of ventilation and reduces the heat to a minimum. g

Another object is to provide spring-seatved `ball bearing contact means for engaging will be understood by` reference to the accompanying drawings, in which- Figure 1 is a plan view of my improved rheostat in its-preferred form; Fig. 2 is a View in cross-section, partly in elevation on the line -ac, Fig. l; and Fig. 3 is a detail, 1n` vertical section, of thejspring-seated ball bearing contact means. y The base of the rheostat made of a single piece of wood, slate or .other insulating and heat absorbing material, and is shown in the drawings lat 1. In the base there is formed an uninterrupted annular undercut retaining groove 2, which groove is openvat the top thereof a predetermined distance to permit of springing lengthwise into place the resistance spiral or coil 3; This coil 3 is held in place with out the use of shellac, cement or other adhesive substance and is prevented from falling out of the groove due to the manner in which the groove is formed and because the opening of the groove is of less diameter than the resistance coil. For making contact with the coil there is provided the contact arm 4, mounted in the center of the base on the pivot 5 by means ofspindle 6, held in lace by a nut 7 and cay V7.

t the outer end 9 of t e arm l is provided a knob 8 held in place by solder or by friction, oi'- otherwise. The knob 8 is hollow and contains a coiled spring 10 suitably fastened at the inner end of the knob; the free end of the spring abuts a metal or carbon ball l1, which engages the individual coils ofthe, resistance conductor, and may be moved backward or forward over the exposedl surface of the conductor so as to ob tain an almost imperceptible variation in current strength. This great advantage makes my improved rheostat regulator in-J VLdispensable' to physicians and dentists, who

require accurate variations in current strength; also to electricians, in connection with the dimmin down or brihtening up of incandescent e ectric lamps or `the purpose of producing electrical effects for the' is preferably and in cases of this kind the knob 8 is mounted on a rod held in position by posts or terminals, so that the spring-seated ball bearing contact means maybe moved up and down or backward and forward in sliding engagement with the resistance coils, according as to whether the said coils lie in vertical or longitudinal grooves.

Thecurrent from the generator or source of supply (not shown) enters the rheostat by means of the wire A to and through the binding post 12, spindle 6, handle or contact arm 4, knob 8 and resistance coil 3, and leaves the rheostat by means of the resistancecoil 3, to and through the binding post 13, back to the source of supply.

The resistance coil 3 at one end thereof near the olf button 14 is fastened by a small screw 15, or other suitable fastening means, and extends all the way around the groove A'to the bindin post 18. The terininals 12 and 13 are fastened to the base 1 by screws, or otherwise, and are connected at the underside of the base by the wire A.

It is to be understood that I do not limit myself t0 the circular arrangement of the retaining groove, and that my- `invention may be embodied in various other forms and vscribed and referred to above.

modificationsl not herein shown or described, without departing from the scope thereof, and 1 do not wish to be considered as conlining myself to the exact construction, instrumentalities or materials shown, de-

Having thus described my invention, what l declare as new and desire to secure by Letters Patent is:

As a new article rof manufacture, a rheostat comprising a one-piece base of insulating material and having an uninterrupted annular undercut retaining groove with an Opening at the top thereof of a predetermined diameter, a hollow resistance coil of greater diameter than the predetermined diameter of the opening of said retaining groove and composed of a series of convolutions, said resistance coil being adapted yto be sprung lengthwise into place in said groove and held in position by the Walls and undercut edges of said groove, a movable contact arm mounted in the center of the base and provided at its outer end with a holloviT knob containing a coiled s ring fastened at the inner end of said kno a metal or carbon ball abutting the free-end of said coiled spring, said ball being adapted to enga e one convolution of said resistance co1 imperceptible variation in electric current strength. A v

In testimony whereof I ax my signature, in presence of two Witnesses.

I HUGO GERNSBACK. Witnesses:

E.l D. JUNIOR', DENA DonAN.

at a time for `obtaining an almost' 

